Synergistic degradation employing photocatalysis and photo-Fenton process of real industrial pharmaceutical effluent utilizing the Iron-Titanium dioxide composite

Abstract

The present work focuses on the treatment of real industrial pharmaceutical effluent, utilizing novel composite beads made up of waste foundry sand (FS) and fuller’s earth (FE), both being good source of iron. These composite beads serves as a surface for the coating of TiO2 along withfacilitating the iron leaching, thus leading to the in-situ dual effect of photocatalysis and photo-Fenton. Optimization of various parameters like a number of beads, treatment time, the dosage of H2O2 using batch and the continuous re-circulation mode reactor has been studied in the sunlight. For the batch scale study, the treatment time of 3.65 h, the number of beads as 98 (98 % surface area covered), and H2O2 dose as 800 mg L−1 were came out to be optimized conditions with maximum % COD reduction. The dual effect was effective in eliminating the complex compounds present in the effluent as confirmed through GC–MS analysis along with the significant reduction in (COD) (71 %) for batch reactor. The treatment time for the real wastewater was reduced by 60−70 min as compared to the exclusive processes of photo-Fenton and TiO2 photocatalysis. In the continuous recirculation mode, 75 % reduction in COD was obtained in 5 h. Further, the bacterial assays proved the disposability of the treated wastewater as per the government regulations. Cost analysis of the overall treatment was also evaluated of the prototype for the complete revelation of the dual process for commercial-scale applications and it was found to be <0.1$ L-1. The composite was successfully recycled for more than 150 cycles without loss in activity of catalyst. The intactness of dual activity during recycles was confirmed through various characterization techniques like XRD, SEM-EDS, FTIR and UV-DRS.